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Description

The BeagleBone is a low-cost, high-expansion board from the BeagleBoard product line. It uses the TI AM3358/9 SoC based on an ARM Cortex-A8 processor core using the ARMv7-A architecture. It is similar in purpose to earlier BeagleBoards, and can be used either standalone or as a USB or Ethernet-connected expansion for a BeagleBoard or any other system. The BeagleBone is small even by BeagleBoard standards yet still provides much of the performance and capabilities of the larger BeagleBoards.

The board uses a TI TPS65217B PMIC to generate stable supply voltages regardless of input power variation. +5V DC power can be supplied to the BeagleBone through a barrel connector or from the mini-USB, both of which are located near the large RJ45 Ethernet connector.

The mini-USB type-A OTG/device client-mode socket is multi-functional. In addition to providing an alternative source of power, it gives access to an on-board front-end two-port USB client-side hub. (This is not related to the separate host-mode USB socket described later). One port of the hub goes directly to the USB0 port of the TI AM3358/9 SoC, while the other port connects to a dual-port FTDI FT2232H USB-to-serial converter to provide board-to-external-host serial communications and/or JTAG debugging. The BeagleBone's Linux serial console is available through this USB serial connection.

The SoC's USB0 connection to the front-end hub works in one of two modes, and you can toggle between them at any time: it either presents the SD card as a mountable USB storage device to the host, or it provides an Ethernet-over-USB networking interface which yields a simple method of quick-start. The Ethernet-over-USB facility is additional to the BeagleBone's normal 10/100 Ethernet interface, which is directly implemented in the SoC rather than hanging off USB as in some other designs. Full IPv4 and IPv6 networking is provided by the supplied Linux system out of the box.

In addition to the USB OTG Device or client-mode facilities already described, BeagleBone also provides one host-mode USB type-A socket on the other end of the board. This is driven from the USB1 connection on the AM3358/9 SoC, and provides access to USB host peripherals such as mice, keyboards, storage, and wifi or Bluetooth dongles, or a USB hub for further expansion.

Specifications

Up to 720-MHz superscalar ARM Cortex-A8

256-MB DDR2 RAM

10/100 Ethernet RJ45 socket, IPv4 and IPv6 networking

MicroSD slot and 4GB microSD card supplied

Preloaded with Angstrom ARM Linux Distribution

Single USB 2.0 type A host port

Dual USB hub on USB 2.0 type mini-A OTG device port

On-board USB-to-serial/JTAG over one shared USB device port

Storage-over-USB or Ethernet-over-USB on other USB device port

Extensive I/O: 2 I2C, 5 UART, SPI, CAN, 66 GPIO, 8 PWM, 8 ADC

+5V DC power from barrel connector or USB device port

Two 46-pin 3.3-V peripheral headers with multiplexed LCD signals

Board size: 3.4" × 2.1" (86.4mm x 53.3mm) -- fits in an Altoid tin

Expansion Boards and Accessories

Capes

A BeagleBone Cape is an expansion board which can be plugged into the BeagleBone's two 46-pin dual-row Expansion Headers and which in turns provides similar headers onto which further capes can be stacked. Up to four capes at a time can be stacked on top of a BeagleBone. An expansion board which can be fitted only at the top of a stack of capes (usually for physical reasons) is a special case of "cape", but this usage is common for display expansion boards such as LCDs (see next section).

Capes are required to provide a 32Kbyte I2C-addressed EEPROM which holds board information such as board name, serial number and revision, although this is typically omitted on simple prototyping capes. Capes are also expected to provide a 2-position DIP switch to select their address in the stack, although this too is often omitted in prototyping capes.

The Capes Registry seeks to index all existing capes and cape concepts, including private projects. A registration page is available to help add capes to the list.

This section lists only those capes which are available commercially or which are close to a production release, as well as open hardware designs.

LCD Displays and Other Expansions

LCD displays for the BeagleBone are typically implemented as capes which plug in as the top board in a stack of capes, for reasons of visibility. Such displays are often larger than the BeagleBone itself, so the normal physical relationship in which a daughterboard is smaller than its host board is inverted. In this arrangement it is the expansion board that provides the physical support for the BeagleBone.

BeagleBone Operating Systems

BeagleBone's default operating system is Angstrom, which ships with the board. This section provides basic information on Angstrom and other operating systems commonly used on BeagleBone. This information may help in making a preliminary choice, but full details should be obtained from the home sites.

Angstrom

Ångström was started by a small group of people who worked on the OpenEmbedded, OpenZaurus and OpenSimpad projects to unify their effort to make a stable and user-friendly distribution for embedded devices like handhelds, set top boxes and network-attached storage devices.
Ångström can scale down to devices with only 4MB of flash storage.

Angstrom uses Busybox for many key utilities, which has both pros and cons. Advantages include requiring less storage space and a smaller memory footprint for many common utilities, which also improves system startup time and performance. The main disadvantages stem from those utilities not mirroring exactly their full-size counterparts. This may be annoying for some, and may also break shell scripts that rely on standard functionality.

Angstrom uses connman for network connection management, but no documentation is available for this currently. Also, man(1) and man pages are not provided by default, nor debugging utilities like strace(1) and tcpdump(1). Getting started may therefore present difficulties, depending on experience.

Debian

The ARM EABI port is the default port of the standard Debian distribution of Linux for the ARM architecture ("armel").
EABI ("Embedded ABI") is actually a family of ABIs, and one of the "subABIs" is the GNU EABI for Linux which is used for this port.
A newer port targeted at newer hardware with another ABI ("armhf") is currently under development and is expected to ship with Debian 7.0 (Wheezy).

The Debian Project is strongly committed to software freedom, and has a long pedigree and a good reputation.

Ubuntu

The vision for Ubuntu is part social and part economic: free software, available free of charge to everybody on the same terms, and funded through a portfolio of services provided by Canonical.

The first version of Ubuntu was based on the GNOME desktop, but has since added a KDE edition, Kubuntu, and a server edition. All of the editions of Ubuntu share common infrastructure and software. In recent years, special emphasis has been placed on netbooks for lightweight, connected, mobile computing, and on the cloud as a new architecture for data centres.

ArchLinux

Arch Linux for BeagleBone is a version of the Arch Linux ARM distribution. This carries forward the Arch Linux philosophy of simplicity and user-centrism, targeting and accommodating competent Linux users by giving them complete control and responsibility over the system. Instructions are provided to assist in navigating the nuances of installation on the varied ARM platforms; however, the system itself will offer little assistance to the user.

The entire distribution is on a rolling-release cycle that can be updated daily through small packages instead of huge updates on a defined release schedule. Most packages are unmodified from what the upstream developer originally released.

Gentoo

Gentoo is a source-based meta-distribution of Linux. Instead of distributing a standard system image built with predefined options, Gentoo gives each user the means to create their own customized system that doesn't contain unused bloat and with minimum dependencies. Upgrades are incremental and under user control, so a Gentoo system is normally always up-to-date and wholesale upgrades are avoided. Being a source-based system, the downside of Gentoo for low-power ARM systems is very long install times for large applications. Cross-compilation on x86 machines and distcc can overcome this problem, but they add complexity.

Board recovery

Software Development

Software development on the BeagleBone is normally no different to any other Linux platform, and typically varies with language and with the IDE used, if any. This section deals only with development issues that are specific to BeagleBone, or mostly so.